Unless confined in fixed ammo, smokeless usually just burns & fizzles. Howja manage to make it go boom?
They duct taped three 3/4” thick by 2” diameter plywood plugs from a hole saw together and pounded it into the barrel. The cannon was made from a chunk of 8” cold rolled steel with a 2” bore about 20” long. Even with black powder it would punch a perfect 8” hole through the plywood sheet and lodge itself a few inches into the ground every time we fired it. It was an impressive boom.